The present invention relates to a system for adjusting or changing idling speed of an automtive engine in accordance with change of electrical installation of a motor vehicle.
In an electronically controlled engine having an electrical engine speed control system, an idling speed control valve is provided in a bypass of a throttle valve for controlling the engine speed during idling of the engine. The idling speed control valve is operated by control pulses to control the flow of air passing through the bypass. The engine speed control system is arranged so as to control the idling speed to a desired idling speed corresponding to a predetermined idling speed in accordance with a control program.
If electrical load is increased by additionally mounting electrical instruments such as lamps, the predetermined idling speed must be increased so as to increase the power of a generator mounted on the engine. In order to increase the predetermined idling speed, another control program and data are stored in a ROM. However, it is difficult for a user to change the program and data in the ROM.